Updater/UpdCheck/main.cpp

124 lines
4.7 KiB
C++

/*
Copyright 2016 Amebis
This file is part of Updater.
Updater is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Updater is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Updater. If not, see <http://www.gnu.org/licenses/>.
*/
#include "stdafx.h"
#pragma comment(lib, "Crypt32.lib")
///
/// Main function
///
int CALLBACK WinMain(_In_ HINSTANCE hInstance, _In_ HINSTANCE hPrevInstance, _In_ LPSTR lpCmdLine, _In_ int nCmdShow)
{
wxApp::CheckBuildOptions(WX_BUILD_OPTIONS_SIGNATURE, "program");
// Inizialize wxWidgets.
wxInitializer initializer;
if (!initializer)
return -1;
wxXmlDocument doc;
// Load repository database.
wxHTTP http;
//wxDateTime timestamp_last_checked;
//http.SetHeader(wxS("If-Modified-Since"), timestamp_last_checked.Format(wxS("%a, %d %b %y %T %z")));
if (!http.Connect(wxS(UPDATER_HTTP_SERVER), UPDATER_HTTP_PORT)) {
wxFAIL_MSG(wxT("Error resolving server name."));
return 1;
}
wxInputStream *httpStream = http.GetInputStream(wxS(UPDATER_HTTP_PATH));
if (!doc.Load(*httpStream, "UTF-8", wxXMLDOC_KEEP_WHITESPACE_NODES)) {
wxFAIL_MSG(wxT("Error reading data file."));
return 1;
}
wxDELETE(httpStream);
http.Close();
// Find the signature first.
wxXmlNode *document = doc.GetDocumentNode();
std::vector<BYTE> sig;
for (wxXmlNode *prolog = document->GetChildren(); prolog; prolog = prolog->GetNext()) {
if (prolog->GetType() == wxXML_COMMENT_NODE) {
wxString content = prolog->GetContent();
size_t content_len = content.length();
if (content_len >= _countof(wxS(UPDATER_SIGNATURE_MARK)) - 1 &&
memcmp((const wxStringCharType*)content, wxS(UPDATER_SIGNATURE_MARK), sizeof(wxStringCharType)*(_countof(wxS(UPDATER_SIGNATURE_MARK)) - 1)) == 0)
{
size_t signature_len = content_len - (_countof(wxS(UPDATER_SIGNATURE_MARK)) - 1);
sig.resize(wxBase64DecodedSize(signature_len));
size_t res = wxBase64Decode(sig.data(), sig.capacity(), content.Right(signature_len), wxBase64DecodeMode_SkipWS);
if (res != wxCONV_FAILED)
sig.resize(res);
else
sig.clear();
// Remove signature for check.
document->RemoveChild(prolog);
break;
}
}
}
if (sig.empty())
wxFAIL_MSG(wxT("Signature not found in the Updater file."));
// Reverse byte order, for consistent OpenSSL experience.
for (std::vector<BYTE>::size_type i = 0, j = sig.size() - 1; i < j; i++, j--)
std::swap(sig[i], sig[j]);
// Create cryptographic context.
HCRYPTPROV cp = NULL;
wxVERIFY(::CryptAcquireContext(&cp, NULL, NULL, PROV_RSA_AES, CRYPT_VERIFYCONTEXT));
// Hash the content.
HCRYPTHASH ch = NULL;
wxVERIFY(::CryptCreateHash(cp, CALG_SHA1, 0, 0, &ch));
::wxXmlHashNode(ch, document);
// Import public key.
HCRYPTKEY ck = NULL;
{
HRSRC res = ::FindResource(NULL, MAKEINTRESOURCE(IDR_KEY_PUBLIC), RT_RCDATA);
wxASSERT_MSG(res, wxT("public key not found"));
HGLOBAL res_handle = ::LoadResource(NULL, res);
wxASSERT_MSG(res_handle, wxT("loading resource failed"));
CERT_PUBLIC_KEY_INFO *keyinfo_data = NULL;
DWORD keyinfo_size = 0;
wxVERIFY(::CryptDecodeObjectEx(X509_ASN_ENCODING, X509_PUBLIC_KEY_INFO, (const BYTE*)::LockResource(res_handle), ::SizeofResource(NULL, res), CRYPT_DECODE_ALLOC_FLAG, NULL, &keyinfo_data, &keyinfo_size));
wxVERIFY(::CryptImportPublicKeyInfo(cp, X509_ASN_ENCODING, keyinfo_data, &ck));
::LocalFree(keyinfo_data);
}
// We have the hash, we have the signature, we have the public key. Now verify.
if (::CryptVerifySignature(ch, sig.data(), sig.size(), ck, NULL, 0)) {
// The signature is correct. Now parse the file.
} else
wxFAIL_MSG(wxT("Updater file signature does not match file content."));
wxVERIFY(::CryptDestroyKey(ck));
wxVERIFY(::CryptDestroyHash(ch));
wxVERIFY(::CryptReleaseContext(cp, 0));
return 0;
}